Borer v. Chapman was a United States Supreme Court case that addressed the issue of whether a state court could enforce a contract that was made in violation of a state statute. The case involved a contract between two parties, Borer and Chapman, in which Borer agreed to pay Chapman a certain amount of money for the sale of a piece of property. The contract was made in violation of a state statute that prohibited the sale of property without a license. The Supreme Court held that the state court could not enforce the contract because it was made in violation of the state statute. The Court reasoned that the state statute was a valid exercise of the state's police power and that the state had the right to protect its citizens from contracts that were made in violation of the law. The Court also noted that the state had the right to protect its citizens from contracts that were made without proper consideration. The Court's decision in Borer v. Chapman established that a state court could not enforce a contract that was made in violation of a state statute. This decision has been cited in numerous cases since then and has been used to support the idea that a state court cannot enforce a contract that is made in violation of the law.

Justice Field delivered the dissenting opinion in Borer v. Chapman, arguing that the majority had misapplied the law and failed to consider relevant evidence. He argued that a contract between two parties should be enforced as written unless there is clear proof of fraud or mistake, which was not present in this case. Furthermore, he noted that while it may have been equitable for one party to receive more than what they were entitled to under the contract due to changed circumstances since its formation, such considerations are outside of a court's jurisdiction when determining whether or not an agreement has been breached. Justice Field concluded by stating his belief that if either party wished for additional compensation beyond what was agreed upon at the time of contracting then they should have negotiated further before entering into any binding agreements.